德兴朱砂红斑岩铜矿石英闪长玢岩的年代学和地球化学特征及地质意义  

Geochronology and Geochemistry of Quartz Diorite Porphyries of the Zhushahong Porphyry Copper Deposit in Dexing and Their Geological Significance

作　　者：李利[1] 倪培[1] 王国光[1] 朱安冬 张映红[2] 梁耀灵 LI Li;NI Pei;WANG Guo-guang;ZHU An-dong;ZHANG Ying-hong;LIANG Yao-ling(State Key Laboratory for Mineral Deposits Research,Institute of Geo-Fluids,School of Earth Science and Engineering,Nanjing University,Nanjing 210023,China;Dexing Copper Mine,Jiangxi Copper Group,Dexing Jiangxi 334200,China)

机构地区：[1]南京大学内生金属矿床成矿机制研究国家重点实验室,地质流体研究所,地球科学与工程学院,南京210023 [2]江西铜业股份有限公司德兴铜矿,江西德兴334200

出　　处：《矿物岩石地球化学通报》2018年第6期1092-1101,共10页Bulletin of Mineralogy, Petrology and Geochemistry

基　　金：国家重点研发计划项目(2016YFC0600206);国家自然科学基金项目(41772063);中国地质调查局地质调查项目(12120114034601)

摘　　要：德兴斑岩铜矿是我国东部最大的斑岩型铜矿,但其成矿时限的研究较为薄弱。为进一步确定德兴斑岩铜矿成矿的持续时间,系统采集了矿田内朱砂红矿区成矿期后石英闪长玢岩脉岩样品进行锆石U-Pb年代学和岩石地球化学研究。结果表明,朱砂红石英闪长玢岩具有高场强元素亏损的弧岩浆特征,指示其岩浆源区可能有俯冲改造的岩石圈地幔物质的加入。前人研究获得的德兴斑岩铜矿成矿岩体的年龄为170Ma,本次研究获得的1个样品中锆石的25个分析点的206Pb/238U的加权平均年龄为(166±1)Ma(MSWD=0.13),两者共同限制了德兴斑岩铜矿的成矿时限不超过4Ma。中侏罗世,伊泽纳崎板块开始向华南大陆俯冲,在华南内陆产生一系列伸展型岩浆作用,朱砂红石英闪长玢岩脉应形成于陆内的局部拉伸构造背景。The Dexing porphyry copper ore field is the largest porphyry Cu system in eastern China.However,the longevity of porphyry mineralization remains controversial.In order to further confirm the time span of mineralization for the Dexing porphyry ore field,this paper focuses on the dike of Zhushahong quartz diorite porphyries which postdated the mineral-ization.Comprehensive zircon U-Pb chronology and geochemistry of the dike were studied.The arc affinity (Nb,Ta and Ti depletion)indicate that parental magma of the dike is probably derived from the melting of metasomatized lithosphere mantie.The age of the Dexing ore-related granodiorite porphyries obtained by previous studies is ca.170Ma,whereas the postore dike emplaced at ca.166Ma,indicating that the porphyry mineralization was finished within 4Ma.In middle Jurassic, the Izanagi plate initially subducted northwestward beneath the South China Block,leading to the formation of intense A type,alkaline and bimodal magmatic rocks in a locally extensional environment.Therefore,the Zhushahong quartz diorite porphyries might have formed in an intra-continental extensional setting.

关 键 词：朱砂红斑岩铜矿 石英闪长玢岩 年代学 岩石地球化学 成矿时限 

分 类 号：P597[天文地球—地球化学]